Dey Anik Kumar, Selvasundarasekar Sam Sankar, Kundu Subrata, Mandal Amal Kumar, Das Amitava, Pramanik Sumit Kumar
Analytical and Environmental Science Division and Centralized Instrument Facility, CSIR-Central Salt and Marine Chemicals Research Institute Bhavnagar Gujarat 364002 India
Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, (CSIR-HRDC) Campus Sector 19, Kamla Nehru Nagar Ghaziabad Uttar Pradesh 201 002 India.
Chem Sci. 2024 Sep 5;15(39):16321-30. doi: 10.1039/d4sc03113j.
The resurgence of interest in sodium-ion batteries (SIBs) is largely driven by their natural abundance and favourable cost, apart from their comparable electrochemical performance when compared with lithium-ion batteries (LIBs). The uneven geographic distribution of the raw materials required for LIBs has also contributed to this. The solid-state electrolyte (SSE) is typically one of the vital components for energy storage in SIBs and for achieving high electrochemical performances. SSEs are preferred over liquid electrolytes primarily due to their enhanced safety and stability, apart from the option of achieving higher energy density. A single sodium-ion selective conductor minimises dendrite formation and cell polarisation, among many other benefits over binary ionic conductors in battery operation. Here, we demonstrate the first example of a sulfonated supramolecular organic two-dimensional (2D) nanosheet as a novel class of single sodium-ion conductors prepared from the self-assembly of a functionalised guanidinium ion (AD-1). Solvent-assisted exfoliation of the bulk powder in water yielded nanosheet morphology, whereas nanotube morphology was achieved in isopropanol (IPA). In contrast, self-assembly with systematic water/IPA solvent ratio variations produced marigold, sunflower, and nanorod morphologies. Thermodynamic parameters, crystallinity, elemental composition, and varying natures of hydrogen bonding in five distinct morphologies were determined using microscopic and spectroscopic studies. The single Na conducting properties of each morphology are correlated in terms of morphology, crystallinity, and the solvent used to achieve that specific morphology. Importantly, with high crystallinity and directional ion channels, 2D nanosheet morphology exhibits the highest single Na-ion conductivity of 3.72 × 10 S cm with an activation energy of 0.28 eV, showing a moderately high Na-ion transference number of 0.83 at room temperature without incorporating any additional sodium salts and organic solvents. This report is believed to be the first to show the significance of nanostructure morphologies in achieving high single-Na-ion transport.
除了与锂离子电池（LIB）相比具有可比的电化学性能外，钠离子电池（SIB）重新受到关注很大程度上是由于其天然丰富性和有利的成本。LIB所需原材料的地理分布不均也促成了这一点。固态电解质（SSE）通常是SIB储能和实现高电化学性能的关键组件之一。SSE优于液体电解质，主要是因为其具有更高的安全性和稳定性，此外还能实现更高的能量密度。单一钠离子选择性导体可最大程度减少枝晶形成和电池极化，在电池运行中比二元离子导体具有许多其他优势。在此，我们展示了一种磺化超分子有机二维（2D）纳米片作为新型单一钠离子导体的首个实例，该纳米片由功能化胍离子（AD-1）自组装制备而成。在水中对块状粉末进行溶剂辅助剥离可得到纳米片形态，而在异丙醇（IPA）中则可实现纳米管形态。相比之下，通过系统改变水/IPA溶剂比例进行自组装可产生金盏花、向日葵和纳米棒形态。使用显微镜和光谱研究确定了五种不同形态的热力学参数、结晶度、元素组成以及氢键的不同性质。每种形态的单一Na传导特性在形态、结晶度以及用于实现该特定形态的溶剂方面相互关联。重要的是，二维纳米片形态具有高结晶度和定向离子通道，表现出最高的单一Na离子电导率3.72×10 S cm，活化能为0.28 eV，在室温下显示出适度高的Na离子迁移数0.83，且无需加入任何额外的钠盐和有机溶剂。据信本报告首次展示了纳米结构形态在实现高单一Na离子传输方面的重要性。
